1. Field of the Invention
The present invention relates to a probe, a method for producing the same, a surface observation apparatus, an exposure apparatus and an information processing apparatus, and more particularly to a probe for evanescent light detection or irradiation for use in a near field optical microscope or the like and a producing method therefor.
2. Related Background Art
Since the development of the scanning tunneling microscope (hereinafter represented as STM) (G. Binnig et al., Phys. Rev. Lett, 49, 57(1982)) capable of directly observing the electronic structure of surfacial atoms of a conductor has enabled the measurement of both monocrystalline and amorphous materials with a high resolution in a real spatial image, the scanning probe microscopes (SPM) are being actively investigated in the field of evaluation of microstructures of various materials. Among the SPM, there are known a scanning tunneling microscope (STM), an atomic force microscope (AFM), a magnetic force microscope (MFM) etc. which detect the surfacial structure by a tunneling current, an atomic force, a magnetic force, a light etc. obtained by positioning a probe with a micro-tip close to a specimen to be evaluated.
Also as an extension of the STM, there has been developed a scanning near field optical microscope (SNOM) (Durig et al., J. Appl. Phys. 59, 3318(1986)) for surveying the surface of a specimen by detecting the evanescent light, leaking from an optical microaperture at the end of a pointed probe, from the surface of the specimen with an optical probe.
Also there has been developed a photon STM (Reddick et al., Phys. Rev. B39, 767(1989)) which is a kind of SNOM and in which the surface of a specimen is surveyed by introducing light from the rear surface of the specimen through a prism and under a total reflecting condition and detecting the evanescent light leaking out to the front surface of the specimen with an optical probe.
The optical probes employed in such near field optical microscope include, for example, an optical fiber sharpened at an end and provided with an optical microaperture at the end, and a cantilever provided at a free end thereof with a needle or tip for light irradiation or light detection to realize the function of an AFM. For the probe of such cantilever type, there is proposed a method of working an end of an optical fiber to form an optical microaperture on a projecting part and bending the optical fiber to make it function as a cantilever (U.S. Pat. No. 5,677,978).
However, the above-mentioned method employing the optical fiber is associated with the drawbacks of low productivity and difficulty in aligning the shape because the probes have to be worked one by one. As a countermeasure, there has been disclosed a probe producing method of transferring a light-transmitting projection formed on a first substrate onto a waveguide formed on a second substrate, then forming a micro-tip layer on the surface of the projection and forming an optical microaperture which have a diameter smaller than the wavelength of the light at the end of the micro-tip layer (Japanese Patent Application Laid-open No. 10-293134). This method is realizable in a batch process, so that it has a high productivity and satisfactory reproducibility of the optical microaperture. Also this method, easily allowing integration and size reduction, enables easy manufacture of plural probes. Also there is obtained an advantage of allowing easy coupling with a semiconductor laser by transferring the projection onto a substrate of a compound semiconductor.
However the probe according to Japanese Patent Application Laid-open No. 10-293134 employs a ceramic material principally composed of silicon oxide or an organic material for the waveguide, and is therefore associated with a drawback that the waveguide shows a large light absorption in a short wavelength region such as ultraviolet region, deteriorating the transmission efficiency.
Also since the projection having the optical microaperture and the waveguide layer are separately prepared and are optically connected in a later step, there is required a complex process in forming the optical connecting portion between the waveguide layer and the optical microaperture, in which there is a drawback to be resolved. Further, the light-transmitting efficiency in the optical connecting portion is decreased, in which there is also a drawback to be resolved.